Andrew Sandstrom piled the six kids — ages 7 and under — into the family minivan Tuesday and dropped his wife off at work, then returned to their Moorhead apartment.

Four hours later, Sandstrom realized that the family’s youngest, 5-month-old Christiana, was still in the van. He went back, got her out of her car seat and brought her into the apartment. She couldn’t be revived.

Police say Christiana died at the scene Tuesday night in what they believe is another case of a child left in a hot vehicle.

“We realize they are in heavy grieving right now,” said Police Lt. Tory Jacobson, of 24-year-old Andrew and Shayna Sandstrom, 27, and the children they are raising at the apartment in the 1100 block of 19th Street S.

Jacobson said his department will investigate Christiana’s death and forward their findings to prosecutors for possible charges, but called it “an accidental death” caused by the father simply forgetting he had left the baby behind in her car seat.

Jacobson said the investigation would reveal details, such as whether the van’s windows were closed.

Temperatures in the Moorhead area climbed into the low 80s by late afternoon and into the early evening Tuesday, according to the National Weather Service. Andrew Sandstrom called police about 8:20 p.m.

“It’s so tragic,” Jacobson said, “even with windows that would be cracked open, clearly, we all know that a vehicle that isn’t running with the air conditioning on,” can heat up sharply and quickly on the inside.

“Even in the shade,” he added, “on a day that doesn’t seem that hot, it gets deadly hot [in a vehicle], especially for an extended period of time.”

In a Wednesday e-mail, Hennepin County Sheriff Richard Stanek warned against leaving children unattended in vehicles, noting that even in mild weather a vehicle’s interior “can quickly become deadly,” and children’s bodies heat up three to five times faster than adults.

10 deaths this year

Christiana is at least the 10th child to have died in a hot vehicle in the U.S. this year, according to KidsAndCars.org, a nonprofit group based in Kansas that persuaded the federal government to track non-traffic tragedies involving children and vehicles.

The group said there were 32 “hot car” fatalities nationwide involving children last year and 49 in 2010.

Amber Rollins, director and volunteer manager for KidsAndCars.org, estimates that nationally, charges are filed about half of the time. How many are actually convicted is unknown.

“If you look at the data, there’s really no rhyme or reason for if or why parents are charged,” she said. “You could take the exact same situation, two different cases. One parent would be charged with felony child neglect and another parent wouldn’t be charged at all.”

There have been four similar deaths in Minnesota since 2001. In three of the cases, no charges were filed. In the fourth, a grand jury indicted the father on a charge of second-degree manslaughter, but the charge was dropped.

Intention and recklessness are key to any possible charges, said Joseph Daly, emeritus professor at Hamline University School of Law.

“A parent who’s busy with all these kids and you know, you forgot. You didn’t do it intentionally ­— that’s for sure — and you may not [have] even done it recklessly,” he said. “Every parent and every potential juror who is a parent understands how something like this could happen … but it would be hard to prove beyond a reasonable doubt.”

A misunderstood problem

Rollins said children being accidentally left behind is a very misunderstood issue.

New parents are often sleep-deprived and stressed, mothers are going through hormone changes and “our human brains don’t function as they normally would under those circumstances.”

The worst thing parents can do, she said, is think that it can’t happen to them.

“Parents make these kinds of inadvertent mistakes every day, but it doesn’t always cost them the life of their child,” Rollins said. “You know, you forget to pick up your kid from soccer practice. It’s the same thing. They just happened to be in a safer place when it happened.”